Differential feed device for sewing machines



Dec. 14, 1 937. F. E BERT DIFFERENTIAL FEED DEVICE FOR SEWING MACHINES 5 She et s-Sheet 1 1 71 ve 7172f Filed Dec. 30, 1935 F. EBERT DIFFERENTIAL FEED DEVICE FOR SEWING MACHINE S 3 S heefs-Sheet 2 Filed Dec. 30, 1955 Attorney Dec.14 ,1937. F.EBERT I 0 02 DIFFERENTIAL FEED DEVICE FOR SEWINGMACHINES Filed Dec. 56, 1955 s Sheets-Sheet 3 Patented Dec. 14, 1937 nmrannn'rmr.

anam FEED DEVICE Foa SEWING canvas Fritz Obemdorf-on-the-Neckar, Germany,

assignor to Mauser-Wake A. G., Oberndorf-onthe-Nectar, Germany, a joint-stock company of Germany Application December so, 1935, Serial No. 56,808 In Germany December 31. 1934 .8 claims. (Cl. 112-408) The invention has for its object a differential feed device for sewing machines, the device being intended for carrier arm sewing machines.

The present invention has for one of its ob- 5 jects to permit the machine to be run at a much higher speed than has been hitherto possible with carrier arm sewing machines having a differential feed, namely, 'at 4000 revolutions The high speed and output of applicant's machine are primarily attributed to the improved arrangement of the driving members, hereinafter described and claimed.

According to the present invention the drive of the main feeding devicels carried in the pedestal of the sewing machine frame, that is, in the most stable part of the machine frame. Fur ried the differential feed device. thermore, the intermediate drive which is controlled by the drive of the main feed is located in the carrier arm from which the difierential feed-is actuated, and is carried close to the pedestal ofthe sewing machine frame and thus on a stable position of the carrier arm.

As driving means for the main feed, there is used a lever oscillated'directly from the main spindle of the sewing machine, in the direction of the carrier arm, which lever, by means of a connecting rod, drives in the direction of the carrier arm an intermediate lever rocking about a transverse axis. On this intermediate lever is carried both the member which moves the main feed device longitudinally, and the member by i which the differential feed device is moved longitudinally, and means are provided to adjust both feed devices independently of each other as regardsthe length of stroke of the feed. The

main adjustment of the feed stroke takes placeby shifting the position at which the connecting rod is attached to the driving lever oithe main feed, with respect to the axis of rotation thereof, that is, by altering the transmission ratio.

fully explained by way of example in the accompanying drawings- Figs. 1 and 2 are a side view and a plan respectively of the complete differential feeddevice with sectionized casing and carrier arm. 3

Fig. 3 is a cross-section through the rear part of the carrier arm. I

Fig. 4 shows a detail which prevents rotation.

Fig. 5 shows in perspective the whole diiferential feed device.

Figs.'6 and 7 are sectional elevation and plan respectively of the feed device guide in a second embodiment.

The sewing machine is provided with the usual carrier am i in which for the most part is car- 15 The main feeding member 2 is located between the two differ-- ential feed members 3. The feed members 2 and 3 carry out the usual reciprocating movements in the longitudinal direction of the carrier arm I, go

and at the same time upward and downward movements. The latter are produced in a known manner and their control device is consequently not described.

The feed devices 2 and 3 are driven by the 25 main spindle t located transversely to the carrier arm I, and which first drives a lever 5 which, in turn, drives both the feed devices 2 and 3, through suitable lever mechanism.

The main spindle 6 drives the main driving :0

the direction of the carrier arm i about a hori- 40 On the intermediate lever which drives, mb zontal transverse axis H2. The latter is mounted the main and the differential feed device, is carried the member for the longitudinal displacement of the former viz., the main feeding frame, at points as far removed from each other as the carrier arm permits, whereby an exceedingly stable" construction is' obtained.

The main feed member can be adjusted with 50 respect to its frame in the longitudinal direction of the carrier arm. In the same way, the differential feed member can also be adjusted longitudinally, care being taken to prevent in both cases,.a rotation of the part in question.

The object of the present invention is more close to the pedestal 0 of the sewing machine housing in the carrier arm I. In order to vary the stroke of the feeding devices 2 and 3, that is to be able to alter the amount of the feeding LIL movement, the drive thereof is adjustable, this being accomplished by the pin l3, by means 01' which the link i0 is connected with the downwardly projecting arm of the driving lever 5, be.- ingadjustable towards and-away from the pivot 8 thereof, whereby the transmission ratio is altered. To this end, the 'connectfng pin i3 is adjustable in aslot ll of the driving lever B. Both the reed devices 2 and 3 are driven by this intermediate driving lever II. Tofcontrol l5 the main feed device 2, its operating connection rod I5 is carried oscillatably on horizontal cross 7 pins I6 mounted on the intermediate lever II which is made double armed, for this purpose. In order to obtain a particularly stable arrangement, the connecting rod I5 is forked and is opened out as wide as the carrier arm I permits. Its two bearings II are oscillatable ,about the pins I5, one of which is supported directly in the intermediate lever I itself and the other in a short arm I8 extending from the boss I9 of the lever Thelever arms I I and I8 together form with the boss a U-shaped lever which is adapted to be oscillatably swung about the transverse spindle l2.

The connecting rod I5 is fitted detachably on the carrier rod 20 of the feed device 2, so that the rod 20 can be moved backward and forward for the purpose of adjusting the main feed device 2 after loosening the fixing device. The carrier rod 20 is displaceable longitudinally in a carrier sleeve 2| of the differential feed device 3, which latter is supported non-rotatably in the slot in the carrier arm I. In the embodiment shown, the connecting rod I5 is axially slotted at the outer end and is firmly clamped in a detachable manner on the carrier rod 20, by means of clamps 22.

If now the driving lever B carries out its oscillating movements, the carrier rod 20 of the main feed device 2 is moved backwards and forwards in the longitudinal direction of the carrier arm I, that is in the direction of feed of the material, and is at the same time moved up and down in known manner by means of the lifting device.

For driving the differential feed piece 3 the intermediate driving part I I, is provided with a further arm 23 directed upward, and fitted on the boss I9 thereof. This drives by means of a connecting rod 24 the differential feed piece 3, and is for this purpose connected with the carrier sleeve 2| thereof. In order to be able to vary the feeding stroke of the differential feed piece 3 independently, the transmission ratio can be varied similarly, as in the case of the main feed drive. To this end,the pin 25 by means of which the connecting rod 24 is attached to the third arm 23 of the intermediate driving lever II, can be adjusted with respect to its axis of rotation I2 by means of a slot 26.

Furthermore, means are provided in order to move the differential feed device 3 with respect to the main feed device 2.

To this end, there is provided at the rear extremity of the carrier sleeve 2| a two-part coupling comprising two sleeves 21, 28 serving as 'a guide in the adjustment. Both sleeves 21, 28 are slotted axially and by means of clamps 29 are firmly clamped on the carrier 2|. The sleeve 21 is connected to the rod 24 and after loosening the sleeve 21 from the carrier sleeve 2|, this, and with it, the differential feeder piece 3 can be shifted backward or forward.

In order to make a. fresh adjustment unnecessary, to prevent any relative turning movement of the sleeves, the front sleeve 28 is provided with a tooth 3B which engages loosely, and is adapted to move longitudinally, in a corresponding slot 3I of the inner sleeve 21. It is thus possible to shift the differential feed piece 3 without a fresh adjustment being necessary.

The main feed device 2 is carried inany suit-- able manner in the differential feeder carrier sleeve 2|. In the embodiment shown in Figs. 6 and 7, it is secured by means of a projection 82 vice, a differential work feed device, an intermediate lever mounted in the carrier arm and rocking about an axis transverse thereto and .located near the pedestal, a. main drive shaft journalled in the pedestal, a lever oscillated by said main drive shaft and having a segmental arm, a link connecting said intermediate lever to the segmental arm, means for fixing the link to said segmental arm at an adjustable distance from the axis of oscillation of said lever, connections between the intermediate lever and the main and auxiliary feed devices, said devices and connections reciprocating longitudinally of the carrier arm, and means in the connections between the intermediate lever and the differential work feed device for independently adjusting the stroke length of said device.

2. Differential work feed mechanism for sewing machines comprising a 'pedestal, a carrier arm extending therefrom, a'main work feed device, a differential work feed device, an intermediate lever mounted in the carrier arm and rocking about anaxis transverse thereto and located near the pedestal, a main drive shaft journalled in the pedestal, a lever oscillated by said main drive shaft, means for driving the intermediate lever with an adjustable stroke amplitude from the oscillatory lever, connections between the intermediate lever and the main and auxiliary feed devices, said devices and connections reciprocating longitudinally of the carrier arm, and means in the connections between the intermediate lever and the differential work feed device for independently adjusting the stroke length of said device.

3. Difierential work feed mechanism for sewing machines, comprising a pedestal, a carrier arm extending therefrom, a main work feed device, adiflerential work feed device, an intermediate lever mounted in the carrier arm and rocking about an axis transverse thereto and located near the pedestal, a main drive shaft journalled in the pedestal, a lever oscillated by said main drive shaft, means for driving the intermediate lever with an adjustable stroke amplitude from the oscillatory lever, connections between the intermediate lever and the main feed device comprising a connecting rod having its end nearer the pedestal in the form of a fork the limbs of which are jointed at spaced points to the intermediate lever, connections between the intermediate lever and the differential work feed device, and means in said last mentioned con nections for independently adjusting the stroke length of said device.

4. Differential work feed mechanism for sewing machines, comprising a pedestal, a carrier arm extending therefrom, a main work feed device, a differential work feed device, an intermediate lever mounted in the carrier arm and rocking about an axis transverse thereto and located near the pedestal, a main drive shaft journalled in the pedestal, a. lever oscillated by 76 aioaeoa said main drive shaft, means for driving the intermediate lever with an adjustable stroke amp tude iromthe oscillatory lever, connections etween the intermediate lever and the main ork teed device, connections between the intermediate lever and the differential ieed device comprising a connecting rod jointed to the intermediate lever, and means ior adjusting the distance of the joint from the axis of rocking oi 'the intermediate lever.

5. Differential work feed mechanism for sewing machines, comprising a pedestal, a carrier arm extending therefrom, a main work feed device, a differential work feed device, an intermediate lever mounted in the carrier arm and rocking about an axis transverse thereto and lo- .cated near the pedestal, a main drive shaft journalled in the pedestal, alever oscillated by said main drive shaft, means for driving the-intermediate lever with an adjustable stroke plitude from the oscillatory lever, connections between the intermediate lever and the main feed device comprising a connecting rod having its end nearer the pedestal in-the form of a fork the limbs of which are jointed at spaced points to the intermediate lever, connections between the intermediate lever and the diflerentiai feed device comprising a connecting rod jointed to the Y intermediate lever, and means for adjusting the distance of the joint from the axis of the intermediate lever.

6. Mechanism according to claim 5, in which the main work feed device is connected to ita being provided to prevent'relative rotation between the sleeves when their axial spacing is adjusted by their clamp means.

7. Mechanism according to claim 5, in which the main teed device is connected to its connecting rod by means of a carrier rod, and the diflerential work feed device is carried by a sleeve slid- I ably mounted onsaid carrier rod and adjustably connected to the connecting rod operating said difierential work feed device, means being provided in the carrier sleeve to guide the main work feed device longitudinally of the said sleeve.

8. Mechanism according to claim 5 in which the main i'eed device is connected to its connecting rod by means of a carrier rod, and the diiferential work feed device is carried by a sleeve slidably mounted on said carrier rod and adjustably connected to the connecting rod operating said diilferential work feed device, means being provided in the connecting rod of the main work feed device for attaching the ,carrier rod to said connecting rod with capacity for their mutual axial adjustment with prevention of relative rotation. v

FRITZ mERT. 

